1. Field of the Invention
The present invention relates to a solid-state image sensor, a method of manufacturing the same, and a camera.
2. Description of the Related Art
It has been required to improve the sensitivity of a solid-state image sensor used in a digital video camera, digital still camera, and the like. Japanese Patent Laid-Open No. 2011-151420 discloses a so-called back-side illumination solid-state image sensor. In the back-side illumination solid-state image sensor, if a semiconductor layer has a thickness of, for example, several μm or smaller, long-wavelength components of incident light having passed through a microlens pass through the semiconductor layer without being sufficiently absorbed. According to Japanese Patent Laid-Open No. 2011-151420, a reflection layer for returning, to the semiconductor layer, light having passed through the semiconductor layer is provided on the whole surface on the wiring layer side of the semiconductor layer. It is possible to improve the sensitivity by returning light having passed through the semiconductor layer to a photoelectric converter included in the semiconductor layer.
In the arrangement in which the reflection layer is provided on the whole surface on the wiring layer side of the semiconductor layer, however, color mixing may occur. More specifically, light which has passed through a first pixel and then obliquely entered a portion of the reflection layer between the first pixel and a second pixel adjacent to it may be reflected by that portion to enter the second pixel. In this case, light which should be detected in the first pixel is actually detected in the second pixel, thereby causing color mixing.